The present invention is directed to a hand-held tool for use as a hammer drill, a powered drill or screw driver and the like and has a detachable chuck, for holding tool bits, secured on a rotary spindle. The chuck has a chuck part in inter-engagement with the rotary spindle with a front end part of the spindle located within a socket-shaped section of the chuck part. The chuck is connected with the rotary spindle so that it can be locked for rotation with the spindle.
In hand-held tools of the above type, it is frequently necessary to use the functional mode of one type of tool in another type of tool. For instance, relatively often the striking action of a hammer drill can be switched off and the hammer drill used as a regular drilling tool. To clamp the tool bit required for such conversion, the hammer drill must have a suitable drill chuck which, as a rule, is effected by providing a chuck with an insertion end arranged to receive the hammer drill.
Such retooling involves the disadvantage that the runout and concentricity of the clamped tool bit cannot be assured and, in addition, the transmittal of torque and percussive force occurs with play or backlash. Moreover, the known hand-held tools have a large over-all length.
It was found impractical to replace the entire chuck instead of so-called adapter solutions, since no solution was known to permit the exchange without involving a high expenditure of time and tooling. For instance, the tool chuck disclosed in DE-OS No. 33 10 371 can be detached from the rotary spindle of the hand-held tool only with special effort requiring additional tools. In the known tool chuck, a set screw has to be loosened by a tool and then an adjusting ring must be moved to a specific location whereby the clamping member releases the connection between the chuck and the rotary spindle. In addition, the connection between the chuck and the rotary spindle disclosed in the above patent publication requires a relatively large guidance region for guiding the chuck on the rotary spindle to assure adequate run-out and concentricity.